The deadline for the duties to go into effect are still three weeks, which may mean the announcements could be a negotiating move.

The country’s new prime minister, Mark Carney, has been called the “Trump whisperer,” and negotiations have been cordial and professional. But it’s been a wild ride.

The letter reiterated Trump’s complaints about dairy quotas, fentanyl and the U.S. trade deficit, which is mostly fueled by American refineries’ thirst for Canadian oil. His social media post caused the Canadian dollar to immediately tumble, indicating the market wasn’t expecting this escalation.

A growing number of migrants in the US are heading north to seek asylum, even as Canada adopts increasingly restrictive immigration policies of its own.

Tensions between the U.S. and its NATO allies have cooled off since most of the alliance's member states agreed to increase their defense spending from 2 percent of GDP to 5 percent by 2035, which many Trump supporters say is proof that his hard-charging negotiating tactics, even among friends, produces results.